Process for weighting of natural and artificial silk fibers



Patented Mar. 21, 1933 UNITED STATES PATENT OFFICE HARRY TZE, OF PATERSON, NEW JERSEY PROCESS FOR WEIGH'I'ING OF NATURAL AND .AIVL-EFICIAL SILK EIIBERS No Drawing. Application filed April 22,

This invention refers to a process for the weighting of natural and artificial s11k fibers with metallic compounds, the term weight- 'ng in this connection being used to designate the method of increasing the Weight and the diameter of the fibers.

In processes heretofore made use of for the wei hting of natural silk and other fibers, in the orm of skeins and woven or knitted fabrics, a number ofchemical substances were brought into contact with the fiber, but all in separate baths, and each containing only one of the necessary weighting or fixing materials. Between each of the baths the grees B. strength at a temperature of 60 degrees F. for some time, and then is rinsed thoroughly with hard water .(6 degrees-9 degrees hardness) in order to hydrolyze the tin-metal salt and to precipitate same on the fiber in the form of stannic -acid--H SnO This stannic acid precipitate is then fixed by a treatment of the silk with di-sodium phos- %hate-HNa PO .12H Oof about 7 degrees strength at about degrees C. The stannic chloride baths and the phosphate baths are alternately repeated until the desired degree of weighting has been obtained, and after each bath or treatment, the silk has to undergo a water rinsing or neutralization as described above. After the last phosphate bath and subsequent rinsing, a treatment in a solution of sodium silicate-Na SiO of about 5 B. strength and at a temperature of 45? C.is applied.

The silk which has been manipulated in this manner and weighted with complex compounds of tin, phosphate and silicate is then rinsed, soaped and soured and is ready .made with other metals.

1932. Serial No. 607,006.

to he further processed by dyeing and finishmg.

The operations described in the foregoing paragraph, as well as other methods I of weighting with various substances, are well known and generally. practised in the industry at the present time On account of the tendering effect on the tensile strength of the fiber of too heavy and too many charges oftin-phosphate compounds, and their costs, and the time necessary for the many baths and washings, the weighting process is generally limited to four applications of tin-phosphate and their attendant rinsings, with an average increase in weight of about 11% for each pass and an aggregate gain of about 45% over theweight of the boiled-off silk.

The purpose of the present invention is to improve upon the methods now in use and to provide a process which is shorter, simpler and less expensive and which at the same time produces considerably more weight in natural silk and other fibers, without impairing their tensile strength nor destroying or diminishing their desirable and characteristic qualities.

As is well known in the chemistry of weighting, natural silk charged with metal salts such as iron, alumina, zinc and tin offer a special affinity for lead compounds. By applying lead-metal salts to previously tin weighted silk, much larger gains in weight per single charge are obtained than those By extensive experiments it was found that the silk-weighting process can be materially simplified and cheapened, when some of the ingredients usually applied in separate baths, namely metal and phosphate compounds, are used in a single bath. The many washings with their necessary losses of materials and the enormous amounts of water can be saved.

In the present invention the silk is treated two or three times in the old and well-known manner with s'tannic-metal salt and (ii-S07 dium phosphate in separate baths, and thorough rinsings after each, and producing a gain of from 20-35% over the weight of the boiled-01f silk. The silk is then brought into silk is then ready a lead-metal salt bath of di-chloride of lead, PbCL of about 6 B. strength to which has .beenadded 15% of decinormal sodium acetate, NaC H O 3I-I O, in order to'as'sist in holding the lead-metal salt-in solution, and which has received a further acid concentration by the addition of 10% tri-basic phosphoric acid con., H PO and 5% isopropylated beta naphtha-line di-sulphonic acid which acts as a colloid. Although so dium acetate is desirable, it is not essential for the purpose of the invention. The treatment lasts for about 30 minutes and the temperature of the bath is maintained at 150 F. In order to neutralize the silk after the above treatment and to improve the fixation of the lead-metal salt, a bath in aqueous alkali, such as a 10% solutionof ammonia carbonate, NH .HCO is recommended. After this step the usual sodium silicate treatment of 3 B. strength at 45 C. is applied. The for soaping and dyeing.

The phosphoric acid 'used in the bath fulfills two distinct functions. First it serves as the producer of the needed high acid concentration which prevents undesirable precipitation on the fiber or in the bath itself, and secondly as the medium to produce the necessary phosphate-metal salt for the fixing of the lead compound on the fiber.

The fibroin of the silk undergoes a chemical change due to the high acid concentration in the lead-metal salt treatment, and forms a homogeneous compound with the tribasic phosphatePb (PO produced in the bath, and the stannic acid-phosphate- SnH PO previou sly deposited in the interior of the fiber by the tin-phosphate treatment, the compound having the empirical formula Pb .Sn. (PO) -CH3 (NH) .COOH etc.

I It is also possible to use instead of phos phoric acid and sodium acetate in the leadmetal salt bath, di-sodium and tri-sodium phosphate with an increased amount of sodium acetate, or to increase the acid concentration of the bath by adding formic or monochloracetic acid, with or without the presence of sodium acetate.

For the protection of the fiber against the tendering influence of the strongly acid bath, an addition of colloids thereto is recommended, such as isopropylated beta naphthaline di-sulphonic acid. These colloids can also be applied to the tin-weighted silk before entering into the lead bath, and not only protect the fiber, but also assist in preventing undesirable precipitation in the bath itself or on the fiber. In this case the addition of the colloid to the weighting bath may be dispensed with.

lit is also possible to treat the silk before entering into the lead-metal solution with acids, such as formic or mono-chloracetic acid, or with salts which will induce the solubility of lead di-chloride in water, such as sodium acetate, and to make this pre-treatment in the presence of protective colloids. The acid concentration of the lead-metal bath may then be diminished. In these cases a change of the silk fiber takes place which promotes a. more equal absorption of the leadmetal salt.

If the tin-weighted silk is treated in a bath of proper proportions and temperatures according to the directions given above, the silk is heavily weighted with lead-metal compounds in a very short time. The precipitation-reaction necessary in the weighting process does not take place in the bath on account of the high acid content, but occurs in the interior of the fiber. It is possible to obtain from 2560% gain in weight by a single im mersion.

'An added advantage of this process is the possibility to carry on the weighting of piecegoods in so-called jiggers, Where the fabrics are treated in full width. As the weightingreaction takes place very quickly, a single immersion will be found sufficient.

The result of the process described is a composite fiber consisting in a minor part of the fibroin of the silk and in a major part of the compound of tin, lead and phosphoric acid, homogeneously combined and which will give olfnone of its elementary component parts when treated with acetic acid or any other liquid with which the silk may come in contact during dyeing and finishing operations or when being worn and exposed to perspiration and other secretions of the human body.

I claim:

1. The-process of weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-weighting agents and fixing baths, subsequently treating the fiber with aqueous solutions con- K taining sodium acetate with isopropylated beta naphthaline di-sulphonic acid, and with di-chloride of lead in the presence of at least one material selected from the group consisting of phosphoric acid, di-sodium phosphate and tri-sodium phosphate, and finally treating said fiber in a bath of aqueous carbonate of ammonia.

2. The process of weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-weighting agents and fixing baths, subsequently treating the fiber with aqueous solutions containing sodium acetate and at least one acid from a group consisting of formic acid and mono-chlor-acetic acid with isopropylated beta naphthaline di-sulphonic acid, and with di-chloride of lead in the presence of at least one material selected from the group consisting of phosphoric acid, di-sodium phosphate and tri-sodium phosphate, and finally treating said fiber in a path of aqueous carbonate of ammonia.

3. llhe process of-weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-weighting agents and fixing baths, subsequently treating the fiber with aqueous solutions containing at least one acid from a group consisting of formic acid and mono-chloracetic acid with isopropylated beta naphthaline di-sulphonic acid, and with di-chloride of lead in the presence of at least one material selected from the group consisting of phosphoric acid, di-sodium phosphate and trisodium phosphate, and finally treating said fiber in a bath of aqueous carbonate of ammonia.

' 4. The process of weighting natural and artificial silk fiber which comprises treating said fiberin separate baths with tin-weighting agents and fixing baths, subsequently treating the fiber in a single bath containing di-chloride of lead, isopropylated beta naphthaline di-sulphonic acid, and sodium acetate in solution with at least one material selected from a group consisting of phosphoric acid, di-sodium phosphate, and trisodium phosphate, and treating said fiber in a bath of aqueous carbonate of ammonia.

5. Theprocess of weighting natural and' artificial silk fiber in separate baths with tin weighting agents and fixing baths, subsequently treating the fiber in a. single bath containing di-chloride of lead, isopropylated beta naphthaline di-sulphonic acid in solution with an acid selected from a group consisting of formic acid and mono-chloracetic acid, and with at least one material selected from a group consisting of phosphoric acid, di-sodium phosphate and trisodium phosphate, and treating said fiber in a bath of aqueous carbonate of ammonia.

6. The process of weighting natural and artificial silk fiber in separate baths with tin weighting agents and fixing baths, subsequently treating the fiber in a single bath containing di-chloride of lead, isopropylated beta naphthaline di-sulphonic acid in solution with sodium acetate and an acid selected from agroup consisting of formic acid and mono-chlor-acetic acid, and with at least one material selected from a group consisting of phosphoric acid, di-sodium phosphate and tri-sodium phosphate, and treating said fiber in a bath of aqueous carbonate of ammonia.

7. The process of weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-weighting agents and fixing baths, subsequently treating the fiber with aqueous solutions con taining sodium acetate with a colloid, and

, with di-chloride of lead in the presence of at least one material selected from the group consisting of phosphoric acid, di-sodium phosphate and tri-sodium phosphate, and finally treating said fiber in a bath of aqueous alkali.

8. The process of Weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-weighting agents and fixing baths, subsequently treating the fiber with aqueous solutions containing sodium acetate and at least one acid from a cup consisting of formic acid and mono-c lor-acetic acid with a colloid, and

with di-chloride of lead in the presence of at least one material selected from the group consisting of phosphoric acid, di-sodium phosphate and tri-sodium phosphate, and-finally treating said fiber in a bath of aqueous alkali.

9. The process of weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-weighting agents and fixing baths, subsequently treating the fiber with aqueous solutions conartificial silk fiber which comprises treating said fiber in separate baths with tin-weighting agents and fixing baths, treating said fiber in an aqueous bath containing a material selected from the group consisting of formic acid and mono-chlor-acetic acid in solution with isopropylated beta naphthaline di-sulphonic acid, and in another subsequent aqueous bath containing di-chloride of lead in the presence of at least one material selected from a grou consisting of phosphoric acid, di-sodium p osphate, and tri-sodium phosphate, and finally treating said fiber in a bath of aqueous carbonate of ammonia.

11. The process of weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with -tin-weighting agents and fixing baths, treating said fiber in an aqueous bath containing a material selected from the group consisting of formic acid and mono-chlor-acetic acid in solution with isopropylated beta naphthaline di-sulphonic acid, and in another subsequent aqueous bath containing di-chloride of lead and sodium acetate in the presence of at least-one material selected from a group consisting of phosphoric acid, di-sodium phosphate, and tri-sodium phosphate, and finally treating said fiber in a bath of aqueous carbonate of ammonia. i

12. The process of weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-Wei hting agents and fixing baths, treating said her in an aqueous bath containing sodium acetate in solution with isoprppylated beta naphthaline di-sulphonic acid, and in another subsequent aqueous bath containing (ii-chloride of lead in the presence of at least one material selected from a group consisting of phosphoric acid, di-sodium phosphate,- and trisodium phosphate, and finally treating sai fiber in a bath of aqueous carbonate of ammonla.

13. The process of weighting natural and artificial silk fiber which comprises treating said fiber in separate baths with tin-Weighting agents and fixing baths, treating said fiber in an aqueous bath containing sodium acetate and a material selected from the group consisting of formic acid and monochlor-acetic acid in solution with isopropy lated beta na hthaline di-sulphonic acid, and in another su sequent aqueous bath containing di-chloride of lead in the presence of at least one material selected from a group consisting of phosphoric acid, di-sodiunr phosphate, and tri-sodium phosphate, and finally treating said fiber in a bath of aqueous carbonate of ammonia.

- 14. A step in the Weighting process of natural and artificial silk fiber which comprises the treatment of the fiber in a single bath comprising lead di-chloride, a colloid, and a material selected from a group consisting of phosphoric acid, di-sodium phosphate and tri-sodium phosphate.

15. A step in the weighting process of natural and artificial silk fiber which comprises the treatment of the fiberina single bath comprising lead di-chloride, sodium acetate, a colloid, and a material selected from a group consisting of phosphoric acid, di-sodium phosphate and tri-sodium phosphate.

16. A step in the weighting process of natural and artificial silk fiber which comprises the treatment of the fiber in a single bath comprising lead di-chloride, a material selected from a group consisting of formic acid and mono-chlor-acetic acid, a colloid, and a material selected from a group consisting of phosphoric acid, di-sodium phosphate and tri-sodium phosphate.

17. A step in the Weighting process of natural and artificial silk fiber which comprises the treatment of the fiber in a single bath comprising lead di-chloride, sodium acetate, a material selected from a group consistingof formic acid and mono-chlor-acetic acid, a colloid, and a material selected from a group consisting of phosphoric acid, di-sodium phosphate and tri-sodium phosphate.

HARRY HINTZE. 

